1. Field of the Invention
The present invention relates to an ultrathin polymer film using a cucurbituril derivative and a method of forming the same. More particularly, the present invention relates to an ultrathin polymer film formed by homopolymerization or copolymerization of a cucurbituril derivative with an organic monomer, and a method of forming the same.
2. Description of the Related Art
Generally, blown film extrusion, calendaring, and laminating techniques have been employed to produce polymer films. Polymer films thus produced have been widely used in various fields as anti-oxidation coatings, anti-smudgy coatings, UV shielding films, hydrophobic films, packing and adhesive films, etc.
In order for polymer films to be used as low dielectric films, etching resistant films, or biosensors for nanoscale semiconductor devices that have received much interest for recent years, the thickness of the polymer films must be controlled to a nano-size range. However, the above-described polymer film production techniques cannot provide polymer films with a nanoscale thickness.
In this regard, the scientific and practical interests in methods of forming polymer films with a nanoscale thickness have been increased and thus extensive studies have been carried out.
Currently known methods for producing polymer films with a nanoscale thickness can be largely divided into two groups: introduction of a polymer solution obtained by dissolving a polymer material in a solvent onto a substrate; and polymerization of monomers on a surface of a substrate.
According to the former methods, polymer films may be formed by dip-coating or spin-coating. However, these methods do not permit the polymer films to have a high crosslinkage and a sufficiently small thickness, i.e., about 100 nanometers or less.
On the other hand, polymer films produced by the latter methods are easily ruptured when separated from substrates and are difficult to be controlled to a nanoscale thickness.
Meanwhile, self-assembled monolayers generally refer to molecular assemblies formed by spontaneous adsorption of specific molecules on the surfaces of substrates. In particular, molecules constituting self-assembled monolayers enable the easy and uniform introduction of specific functional groups onto the surfaces of substrates due to their directionality. Therefore, self-assembled monolayers have been widely utilized in protection of substrates against chemical materials, or in detection and analysis of biological materials, such as proteins or DNAs, through appropriate selection of functional groups of molecules constituting the self-assembled monolayers.
Many attempts to produce various types of polymer films based on the above-described characteristics of self-assembled monolayers have been made for recent years. In particular, many researchers have attempted to produce ultrathin polymer films with a thickness of 5 nm or less by synthesizing molecules with UV-induced polymerizable functional groups, forming self-assembled monolayers on surfaces of substrates using the molecules, and exposing the self-assembled monolayers to UV light [J. Am. Chem. Soc. 1995, 117, 5212, Langmuir 2003, 19, 2466].
However, most currently available ultrathin polymer films cannot be separated from the surfaces of substrates. Even when the separation of ultrathin polymer films from the surfaces of substrates is possible, the ultrathin polymer films cannot retain their film shapes after the separation, which considerably restricts the application of the ultrathin polymer films.